Anthropogenic activities cause environmental degradation-related problems. However, people fail to perform pro-environmental behaviours because they believe that they cannot make a difference or they focus on short-term benefits. Interventions that address specific target groups aimed at breaking barriers and changing behaviours are required. To teach young learners, environmental education using digital games can be a more effective instructional method. This mixed-methods study, conducted among high school students in India, examined differences in pro-environmental attitudes and behaviours between students who played a game called EnerCities and those students who did not play that game. Significant differences existed between the two groups considering the unidimensional and multi-dimensional properties of the New Ecological Paradigm (NEP) scale. Thematic analysis with an inductive approach identified from the interview data: How EnerCities changed participants' environmental attitudes? This study finds implications for implementing games and using the NEP to examine environmental attitudes of high school students in India.